Hardening process for photographic light-sensitive elements

ABSTRACT

A PROCESS FOR HARDENING A SILVER HALIDE PHOTOGRAPHIC LIGHT-SENSITIVE ELEMENT, WHICH COMPRISES PROCESSING THE LIGHT-SENSITIVE ELEMENT IN A PROCESSING BATH CONTAINING FORMALDEHYDE AND AROMATIC DIALDEHYDE REPRESENTED BY THE GENERAL FORMULA:   (O=CH)2,R,R&#39;&#39;-BENZENE   WHEREIN R AND R&#39;&#39; EACH REPRESENTS ONE MEMBER SELECTED FROM THE GROUP CONSISTING OF A HYDROGEN ATOM, A LOWER ALKYL GROUP HAVING 1-5 CARBON ATOMS, AND A GROUP CAPABLE OF INCREASING WATER SOLUBILITY, SAID GROUP BEING A MEMBER SELECTED FROM THE GROUP CONSISTING OF SO3H, COOH, OH AND THE NA K OR NH4 SALT THEREOF.

United States Patent Office Patented July 18, 1972- US. CI. 96-50 PT 6 Claims ABSTRACT OF THE DISCLOSURE A process for hardening a silver halide photographic light-sensitive element, which comprises processing the light-sensitive element in a processing bath containing formaldehyde and aromatic dialdehyde represented by the general formula? R CHO wherein R and R each represents one member selected from the group consisting of a hydrogen atom, a lower alkyl group having 1-5 carbon atoms, and a group capable of increasing water solubility, said group being a member selected from the group consisting of SO H, COOH, OH and the Na K or NH, salt thereof.

The present invention relates to a process for hardening emulsion layers for silver halide photographic light-sensitive elements.

When a silver halide photographic light-sensitive element is processed at high temperature or it is processed for a long time in solutions of high pH, as is the case with the processing of reversal color photographic materials, it is necessary to harden the emulsion layers thereof at an early stage of the processing to prevent the emulsion layers from being damaged during the processing. The examples of such hardening process are the treatment of photographic materials with an aqueous alkaline solution of an aliphatic aldehyde or with an aqueous solution of aluminium sulfates.

In general, the hardening solution containing an aldehyde harden emulsion layers effectively but their practical applications are limited by the fogging activity of the aldehyde. Therefore, a good hardening solution should have the following features:

(1) The hardening solution should harden emulsion layers effectively without giving chemical fogs to the emulsions. Aldehydes often give fogs to silver halide emulsions owing to' their reducing property, therefore, for hardening it is important to overcome such a difliculty.

(2) The hardening solution should afford the quick hardening. That is, the emulsion layers should be hardened within one minute in a pre-hardening bath, or when the hardeners are in developers, they should be hardened quickly at the beginning of the development.

(3) The suflicient hardening should be attained by possibly small content of hardening agent in solution. The benefit of reducing hte concentration of hardening agents lies not only in decrease in chemical cost but also in elimination of their undesirable secondary effects and the easier scavenging of residual hardening agents after the prehardening process. A large quantity of an aldehyde is necessary for the hardening at low pH. To reduce the aldehyde concentration, the pH of the bath must be increased,

which results in the increase in fog formation. Therefore, an improved hardening agent should have a suflicient hardening effect even in solution of low concentration and low pH.

(4) The hardening agent should not react with colorforming materials (couplers) in the emulsion layers.

Therefore, an object of the present invention is to provide a hardening process for photographic light-sensitive elements capable of performing effective hardening without accompanying the aforesaid technical difliculties.

More practically, an object of the present invention is to provide a hardening process for photographic light-sensitive elements capable of exhibiting effectively the hardening effect even at a low concentration of hardening agent in a very short period of time with less formation of fogs and without accompanying undesirable reaction with couplers.

Another object of this invention is to provide a hardening agent capable of being used not only in hardening bath but also in a hardening developer by which hardening is proceeded simultaneously with the course of development.

The inventors have found that the above objects of this invention can be achieved by incorporating formaldehyde and one or more aromatic dialdehydes represented by the following general formula in a processing solution:

R CHO wherein R and R each represents a hydrogen atom, a lower alkyl group such as a methyl group or an ethyl group, a group capable of increasing water-solubility, such as -SO H, COOH, or -OH, Na, K or NH, salt thereof.

The typical examples of the aromatic dialdehydes used in the present invention are as follows:

(1) Phthalaldehyde OHO (2) Isophthalaldehyde (4) 2-methylterephthalaldehyde CHO I @CH] l O HO 3 (5) 4,5-dimethylphthala1dehyde (6) 4-hydroxyphthalaldehyde (7) S-methylisophthalaldehyde CHO C CHO (8) Z-hydroxyisophthalaldehyde (9) 4 hydroxyisophthalaldehyde (10) 2,4-dihydroxyisophthalaldehyde III H (1 1) 4,6-dihydroxyisophthalaldehyde 0- O m QM 4.. o

12 4,S-dihydroxyisophthalaldehyde CEO ( 1 3 4-hydroxy-S-methylisophthalaldehyde YdI' XY-s-methvlisoghthalaldehyde i I CHO CHO

( 15) 4,6-dimethylisophthalaldehyde (EHO r 330 19) 4-sulfoisophthalaldehyde An additive amount of the dialdehyde is 0.5v-1f5 g. per

one liter of the processing solution. And an additive amount of formaldehyde is 5-30 ml. of a 37% aqueous solution per one liter of the processing solution, preferably 20 ml. of a 37% aqueous solution.

Japanese patent publication No. 27,560/64, (US. Pat. 3,220,849, to Baden and Bard filed Feb. 16, 1962) discloses a process of hardening by a mixture of the abovementioned dialdehyde and formalin is excellent on the 7 point of less fog formation as compared vvith the, known combination of aldehydes. Furthermore,thewconibination of this invention is more profitable, because .the solution,

of this combination is more stable and hasJongerlife than the above-mentioned known combination.

Furthermore, since preferable concentration of the dial:

I dehyde for practical hardening'is low enough to avoid undesirable secondary eflfects of the aldehydes such as increase in fog and side reaction with couplers Therefore, the hardening agent of this invention can be used not only for pre-harclener but also for a devel oper to enable simultaneous hardening and development intonev processing 'bath without much increase in developer tog.

EXAMPLE 1 After exposing, a silver halide emulsion layer was subjected to the following photographic processings at 30 C.

Process: Hardening Washing Development Washing Fixing Washing Processing timeffimin.) 1

Il a f l ow n ..aiahtlsinggi92995- were employed.

Composition A: 5.4 ml. of sulfuric acid (1:1), 150 g. of sodium sulfate and 20 g. of sodium acetate; composition B: 5.4 ml. of sulfuric acid, 150 g. of sodium sulfate,

20 g. of sodium acetate, and 20 ml. of formalin (37%); composition C: 5.4 ml. of sulfuric acid, ,150 g..of sodium sulfate, 20 g. of sodium acetate, 1.0g. of phthaldialde hyde; composition D:- 4 ml. of sulfuric. acid, 150 g of sodium sulfate, g. of sodium acetate, and 1.0 g. of isoph: thalaldehyde; composition E: 5.4 ml. .of sulfuric acid, 15.0 g. of sodium sulfate, 20g. of sodium acetate and 1,0 g. o f terephthalaldehyde; composition F: 5 .4 ml. of sulfuric acid, 150 .g. of sodium sulfate, 20 g. of sodium acetate, 1.0 g. of phthaldialdehyde, and 20 ml. of formalin (37%); composi: tion G: 5.4. ml. of sulfuric acid, 150 g. of sodium sulfate, 20 g. of sodium acetate,. l,0 g. of isophthalaldehyde,,20 ml. of formalin (37%); compositionHpSAnil. of sulfuric acid, 150 g." of sodium sulfate, 20 g. of sodium acetate, 1.0 g. of terephthaldialdehyde, and 20 ml. of formalin (37%); composition 1: 5.4 ml. of sulfuric acid (1:1), 150 g. of so dium sulfate, 20 g. of sodium acetate, 1.0 g; of 4-hydroxyphthalaldehyde and 20 cc. of formalin (37%); composition I: 5.4 ml. of sulfuric acid (1:1), 150 g. of sodium sulfate, 20 g. of sodium acetate, 1.0 g. of 4-hydroxy-5-methf ylisophthalaldehyde and 20 cc. of formalin (37%); composition K: 5.4 ml. of sulfuric acid (1:1), .150 g. of sodium sulfate, 20 g. of sodium acetate, 1.0 g.'of 4,6-dimethyli'so phth-alaldehyde and 20 cc. of formalin (37%); composition L: 5.4 ml. of sulfuric acid, 150 -g'-. of sodium sulfate; 20 g. of sodium acetate, 1.0"g.of 2,S-dicarboxyterephthalaldea 'hyde and 20 cc. of formalin (37%); ompos-ition M:5.f1 ml. of sulfuric acid (1:1), 150'1g.;"of sodium sulfate, 20g, of sodium acetate, 1.0 g. ofj4-sulphoisoplith-alaldehyde and 20 cc. of formalin (37%). i I L 'Each of the compositionswasdiluted with water to one liter in volume, the pH of which was 4.8. t

The developer was a conventional blacl; and white developer for positive film containing metol and hydr' oquinone and the fixing solution was a conventional acid hardener fixer. a V

The fog densities of the black and white t 1 e'gative' image thus obtained are shown in the following table. The forma tion of fogs, increased slightly in'th'e case of employing phthalaldehyde but such an extent of increase would not affect much on the photographic qualifies, t, On the other hand, the melting point of the emulsion layers thus processed were measured for, knowing the ex,- tent of the hardness of the emulsion layers, the results of which are also shownin the same table. This valiie is the temperature when after washing the film subjectedflto the hardening processing with water, the emulsion layer was swelled and dissolved in the solution in the case of heating the film to the temperature in an aqueous 0.2 N sodium hydroxide solution. i i

As shown in the above table, by using formalin and the aromatic dialdehyde simultaneously, the excellent harden-'- ing effect which hadnever been obtained 'by using each of the aldehydes individually-was obtained without being accompanied by an increase in formation of fogs. By -the application of the hardening procedure of thisinve'ntion, the damages to the surface of the emulsion layers of light-sensitive elements when they were processed in an automatic developing machine employing vigorous stirring was remarkably reduced.

EXAMPLE 2 After exposing, the gelatino silver halide emulsion layer containing a magenta coupler was subjected to the following reversal color developing procedures: (processing temperature: 30 C.).

Process: Processing time (min.) Hardening 1 Washing 1 1st development 3 Washing 0.5

Reversal exposure (uniform exposure at 8000 luxes-sec.

over the surface of emulsion layer) "The composition of the hardening bath was the same in Example 1. Other compositions for the above-mentioned processings are shown below.

Composition for the 1st developer G. N-methyl-p-aminophenol sulfate 2.0 Sodium sulfite 90.0 Hydroquinone 8.0 Sodium carbonate (monohydrate) 52.5 'Potassium bromide 5.0 Potassium thiocyanate 1.0 Water to make 1 liter.

Composition for the 2nd developer Benzyl alcohol ml 5.0 Sodium sulfite g 5.0 3-methy1- 4 amino-N-ethyl N methane sul-fonamide ethyl-aniline sulfate g 1.5 Potassium 'bromide g 1 Sodium phosphate, tribasic g 30 Sodium hydroxide g 0.5 Ethylenediamine (aq. soln.) ml.. 7

Water to niake 1 liter. i

7 Composition for the bleaching bath Water to make-l liter.--

The photographic properties of the reversal color images thus obtained are shown in the following table. As shown in the results, the photographic properties .were not deteriorated. as compared with-those obtained without using the dialdehyde and also in someof them, themaxi mum density was increased. Also, the strength of. the emulsion layers processed in accordance with the present invention was very excellent as shown in Example 4.

Hardening Maximum solution Sensitivity den None-.

1. so 2. oo

- 1. so 2. so

1. so 2. 7s

- 1. so 2. 1o

- 1. so 2. 7s

EXAMPLE 3 After exposure, a reversal color photographic lightsensitive film having a light-sensitive emulsion layer containing a commercially-available coupler was processed as in Example 2 except that the following compositions were employed as the hardening solutions.

Sodium A B C D Sodimn sulfate, g 200 200 200 200 Sodium acetate, g 20 20 20 20 Potassium iodide, ml 20 20 2o. 20 Potassium bromide, g- .3 2. 3 2. 3 2. 3 Formalin (87%), m1---. 15 15 15 Isophthnlaldehyde, g-.. 1. 1. 0 Water to make one liter.

N orn.'lhe pH was 4.3.

The results showed that the photographic properties of the sample processed using hardening solution D were same as those of a sample processed using hardening solution A. onthe otherhand the strength of the emulsion l y r fth p p ocessed. b using hardening solution D was higher than those samples processed by using hardening solution B and hardening solutionC respectively as shown in the following table.

Hardening solution: Melting point, C.

57.0 I B 58.5 c 58.5 1 63.0

' EXAMPLE 4 I After exposing, a gelatino silver'halide emulsion layer was subjected to the following photographic processings:

8 Process: 2 Processing time (min.) 'Hardeningn'n Fixing t Washing 1.5

The processes were. carried out at C. The composition of the developer was as follows, .while the fixing solution was a usual acid fixing solution. 1

Composition for the developer A B N-methyl-p-aminophenol sulfate, g 4. 5 4. 5 Sodium carbonate (monohydrate), g.. 41 41 Sodium sulfite, g 15 15 Hydroquinone, g...v 8. 0 8. 0 Potassium bromide, 3. 0 3. O fi -nitrobenziurldazole, g 0. 1 0.1 Formaldehyde (37%) ml- 2 2-methyl-terephthalaidehyde, g 0. 5 Sodium hydroxide;g- Y r r H 0. 1 0.1 1 Sodium sulfate, 2 4

Water to malts one liter. J

The processings were conducted in an automatic developing machine with 'stirring vigorously. After the processings; the formation of mechanical damage to the sur'-' face of-the emulsion layer was detected. This showed that the damage in the case of using hardening solution A was reduced to A of the damage in the case of using hardening solution B. The fog density was 0.10 in both cases.

What is claimed is: 1. In a process for hardening a silver halide photographic light-sensitive element, the improvement which comprises processing the light-sensitive element in a processing hath containing formaldehyde and an aromatic dialdehyde selected from the group consisting phthaldialdehyde,

isophthaldialdehyde, terephthaldialdehyde, Z-rnethylterephthaldialdehyde, 4-hydroxyisophthalaldehyde, 4-hydroxyphthalaldehyde, 5 -methylisophthalaldehyde, Z-hyfdroxyisophthalaldehyde, 4- hydroxyisopthalaldehyde, 4,6-dihydroxyisopthalaldehyde, 4,5 dihydroxyisophthalaldehyde,

' 45hydroriy-S-methylisophthalaldehyde,

Z-hydroxy:S-methylisophthalaldehyde, 4,6 dimethylisophthalaldehyde,

2,5 -d ihydroxyterephthalaldehyde, 4,6-dihydroxyisophthalaldehyde,

2,5-dicarboxyterephthalaldehyde an 4-sulfoisophthalaldehyde, 1

said aromatic dialdehyde capable of maintaining a group capable of increasing water solubility on the aromatic nucleus, said group being a member selected from the group consisting of SO H, COOH, OH, and the Na, K, or NH salt thereof.

2'. The process a's'claimed in claim 1 wherein the amount of the dialdehyde is 0.5-l.5 g. per 5-30 ml., of an aqueous solution'of formaldehyde when the concentration of the formaldehyde solution is about 37% by weight.

3. The process as claimed in claim 1 wherein said processing bath is a pre-hardening bath.

"4.,The process as claimed in claim 1 wherein said processing bath is a developing bath.

5. The process of claim 2 wherein the amount of dialdehyde is 0.5-1.5 g. per 20 ml. of an aqueous solution of formaldehyde when the'concentration of the formaldehyde solution is about 37 by weight.

9 10 6. The process of claim 1 wherein the pH is 4.8. OTHER REFERENCES References Cited l8/Iason, Photographrc Processmg, pp. 151-152, 185- UNITED STATES PATENTS 3 5 5 32 2 1971 ill 9 111 5 NORMAN G- TORCHIN, Primary Examiner 2,629,659 2/1953 Mueller 96111 M. F. KELLEY, Assistant Examiner 3,102,811 9/1963 Barney 96-48 3,168,400 2/1965 Blackmer 9656 US. Cl. X.R. 3,451,817 6/1969 Bard 96111 3,220,849 11/1965 Baden 96-111 111 

